/*
===========================================================================
Copyright (C) 1999-2005 Id Software, Inc.
 
This file is part of Quake III Arena source code.
 
Quake III Arena source code is free software; you can redistribute it
and/or modify it under the terms of the GNU General Public License as
published by the Free Software Foundation; either version 2 of the License,
or (at your option) any later version.
 
Quake III Arena source code is distributed in the hope that it will be
useful, but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.
 
You should have received a copy of the GNU General Public License
along with Foobar; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
===========================================================================
*/

#include "../game/q_shared.h"
#include "qcommon.h"
#include "client.h"

/*
==============
CL_Netchan_Encode
 
	// first 12 bytes of the data are always:
	long serverId;
	long messageAcknowledge;
	long reliableAcknowledge;
 
==============
*/
static void CL_Netchan_Encode( msg_t *msg )
{
    int serverId, messageAcknowledge, reliableAcknowledge;
    int i, index, srdc, sbit, soob;
    byte key, *string;

    if ( msg->cursize <= CL_ENCODE_START )
    {
        return;
    }

    srdc = msg->readcount;
    sbit = msg->bit;
    soob = msg->oob;

    msg->bit = 0;
    msg->readcount = 0;
    msg->oob = 0;

    serverId = MSG_ReadLong(msg);
    messageAcknowledge = MSG_ReadLong(msg);
    reliableAcknowledge = MSG_ReadLong(msg);

    msg->oob = soob;
    msg->bit = sbit;
    msg->readcount = srdc;

    string = (byte *)clc.serverCommands[ reliableAcknowledge & (MAX_RELIABLE_COMMANDS-1) ];
    index = 0;
    //
    key = clc.challenge ^ serverId ^ messageAcknowledge;
    for (i = CL_ENCODE_START; i < msg->cursize; i++)
    {
        // modify the key with the last received now acknowledged server command
        if (!string[index])
            index = 0;
        if (string[index] > 127 || string[index] == '%')
        {
            key ^= '.' << (i & 1);
        }
        else
        {
            key ^= string[index] << (i & 1);
        }
        index++;
        // encode the data with this key
        *(msg->data + i) = (*(msg->data + i)) ^ key;
    }
}

/*
==============
CL_Netchan_Decode
 
	// first four bytes of the data are always:
	long reliableAcknowledge;
 
==============
*/
static void CL_Netchan_Decode( msg_t *msg )
{
    unsigned long reliableAcknowledge, i, index;
    byte key, *string;;
    int	srdc, sbit, soob;

    srdc = msg->readcount;
    sbit = msg->bit;
    soob = msg->oob;

    msg->oob = 0;

    reliableAcknowledge = MSG_ReadLong(msg);

    msg->oob = soob;
    msg->bit = sbit;
    msg->readcount = srdc;

    string = (byte *)clc.reliableCommands[ reliableAcknowledge & (MAX_RELIABLE_COMMANDS-1) ];
    index = 0;
    // xor the client challenge with the netchan sequence number (need something that changes every message)
    key = clc.challenge ^ LittleLong( *(unsigned *)msg->data );
    for (i = msg->readcount + CL_DECODE_START; i < msg->cursize; i++)
    {
        // modify the key with the last sent and with this message acknowledged client command
        if (!string[index])
            index = 0;
        if (string[index] > 127 || string[index] == '%')
        {
            key ^= '.' << (i & 1);
        }
        else
        {
            key ^= string[index] << (i & 1);
        }
        index++;
        // decode the data with this key
        *(msg->data + i) = *(msg->data + i) ^ key;
    }
}

/*
=================
CL_Netchan_TransmitNextFragment
=================
*/
void CL_Netchan_TransmitNextFragment( netchan_t *chan )
{
    Netchan_TransmitNextFragment( chan );
}

/*
===============
CL_Netchan_Transmit
================
*/
void CL_Netchan_Transmit( netchan_t *chan, msg_t* msg )
{
    MSG_WriteByte( msg, clc_EOF );

    CL_Netchan_Encode( msg );
    Netchan_Transmit( chan, msg->cursize, msg->data );
}

extern 	int oldsize;
int newsize = 0;

/*
=================
CL_Netchan_Process
=================
*/
qboolean CL_Netchan_Process( netchan_t *chan, msg_t *msg )
{
    int ret;

    ret = Netchan_Process( chan, msg );
    if (!ret)
        return qfalse;
    CL_Netchan_Decode( msg );
    newsize += msg->cursize;
    return qtrue;
}
